Cognitive Behavioral Therapy (CBT) is the leading evidence-based psychotherapy for depression, which affects 18.5% of Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND) Veterans (hereafter referred to as OEF/OIF). Yet, OEF/OIF Veterans had only a 30% average reduction in mean depression scores from the initial to later phase of treatment. This was true despite the rigorous training and certification procedures for VA CBT-D. Improving the rate of depression recovery and remission is vital to enhance OEF/OIF Veteran?s ability to improve work and home adjustment and overall quality of life. Broad access to all key ingredients of CBT, including skills practice (homework), is associated with improved and faster recovery from depression. OEF/OIF Veterans and patients with depression have reported many barriers (i.e., time, chaotic lifestyles, and low energy) to following through with their skills practice assignments. In the absence of targeted strategies/interventions to address the barriers that prevent CBT skills practice, OEF/OIF Veterans will remain unable to reap the full benefits/effects of CBT. With specific tailored interventions to address this gap in treatment, OEF/OIF Veterans will improve rates of recovery from depression, diminished home and work adjustment, and poor quality of life. Leveraging the technological savvy of this generation of Veterans to improve access to CBT skills practice is a logical tactic to address this gap in treatment. Smartphone apps have been identified as a useful widely-used tool to improve the effectiveness of psychological treatments. There is, however, a paucity of empirical studies on the use of mobile apps in the treatment of depressed OEF/OIF Veterans and in psychological treatment overall. The promising pilot results of a comprehensive tailored smartphone app for CBT skills practice for OEF/OIF Veterans (?CBT MobileWork-V?), leads us to propose a larger-scale randomized clinical trial (RCT) to measure the efficacy of CBT enhanced with CBTMobileWork-V (the experimental arm) for improving CBT understanding and skill acquisition and depressive symptoms, in OEF/OIF Veterans with depression compared to standard CBT-D. Specifically, over a 27-month period we propose to randomize 268 eligible OEF/OIF Veterans with depressive symptoms, to either CBT augmented with the comprehensive CBT skill training smartphone app CBT MobileWork-V or standard CBT-D with traditional skills practice methods (i.e., paper and pencil). The Specific Aims of this study are: Primary Aim 1) To assess whether CBT-D augmented with CBT MobileWork-V (hereafter referred to as CBT- D+) promotes greater CBT understanding and skill acquisition compared to traditional CBT-D. Primary Aim 2a) To examine the short-term effect in depressive symptoms after 12 weeks of CBT-D+ versus standard CBT-D. Primary Aim 2b) To examine the long-term effect in depressive symptoms at 6 months post treatment of the CBT-D+ intervention versus traditional CBT-D.